Police trial lie detectors on sex offenders

Police are carrying out a trial to determine whether lie detector tests are a useful way of bringing about the conviction of criminals.

The test is being led by officers in Hertfordshire and involves testing ‘low level’ sex offenders.

Police are trialling the lie detector approach

The Association of Chief Police Officers (Acpo) said the research at ‘very early stages’.

Hertfordshire police is reported to have completed a successful pilot scheme in November in which 25 offenders were tested.

Many were exposed as being a higher risk to children than originally thought, The Times reported, and a further 12-month trial has been approved to begin in April.

An Acpo spokesman said: ‘We monitor any new approaches or technology which could provide a positive benefit in helping investigate crime, support victims and put offenders before the courts.’The Acpo Homicide Working Group provides advice to the police service on the use of polygraph techniques and will follow with interest the latest study led by Hertfordshire Constabulary.’Polygraph techniques are complex and are by no means a single solution to solving crimes, potentially offering in certain circumstances an additional tool to structured interrogation.’These initial trials are in their very early stages and we will follow their progress, working with chief officers across the country to provide further guidance if necessary.’Whether these techniques are adopted elsewhere in the country is a matter for individual Chief Constables.’

The newspaper said the tests were being used to help decide whether to charge suspected criminals for the first time in British policing history.

Although Devon and Cornwall Police had used a lie detector on a single occasion when investigating a violent crime, the Hertfordshire trial was the first use of pre-conviction testing in the UK, it said.

Offenders can only take the tests if they volunteer, and evidence gained is not admissible in court, it added.

Detective Chief Inspector Glen Channer, head of the the force’s child protection unit, said the polygraph was an ‘added weapon in our armoury of investigative techniques’.

He said the tests were carried out by accredited practitioners in a scientific environment and were not relied upon on their own.